Farrowing pens, or crates, have been utilized for many years in an effort to reduce the incidents of accidental injury or killing of the piglets by being laid or stepped upon by the sow when the latter changes position within the pen during and after farrowing. Such prior pens, or crates, because of inherent structural design were beset with one or more of the following shortcomings: (a) they were incapable of properly confining sows of varying sizes and shapes; (b) they failed to provide adequate nursing space for the piglets; (c) one or more piglets were susceptible to becoming trapped for prolong periods of time or crushed to death between a wall of the pen and the confined sow; (d) cleaning of the pen was a frustrating and time consuming operation; (e) confinement of the sow within the pen was such that the sow was susceptible to injuring herself when changing position; and (f) the dimensions of the piglet access opening to the compartment in which the sow was confined could not be varied without requiring substantial disassembly of the pen.